Shrink-head casing for ingot molds



Patented Dec. 25, 1928.

EMIL eArHMAN-N, or BALTIMORE, MARYLAND.

SHRINK-HEAD CASING FOR INGOT MOLDS.

' Application filed October 28, 1926. Serial No. 144,800.

This invention relates to what are known as feeders, hot tops, or shrink head casmgs for ingot molds, in which provision is mad-e for conserving the heat of the molten metal in the top portion of the mold, in order that such portion of the metal may be maintained in a liquid condition, and thus serve to lill the pipe. or cavity in the upper part of the body of the ingot, and thus reduce the unsound or pipe-containing portion of the ingot in the top of the mold.

Such shrink head casings have usually been mad-e of refractory material such as re clay, and it has heretofore been proposed to construct feeders with chambers for containing combustible material such as coal, charcoal, or coke which, when burned, serves to conserve the heat of the ingot to some extent, and to thus reduce pipe. It has also been heretofore proposed to. make shrink head casings of combustible material such as coal, charcoal, coke or the like, and I therefore do not claim as my invention such subject matter.

According to my present invention, I construct a shrink head casing by forming the body thereof of slowly combustible material such as coke or coal or charcoal and a suitable binder such as Portland cement, and I surround this casing with a non-combustible material preferably composed of `silica sand, cement, and a small percentage of molasses. This non-combustible material is so applied as to form a` sheath or casing for the combustible material, which is closed at all points except at the top, where it is provided with a few or a plurality of openings which serve as vent holes.

Such shrink head casing may be made in various shapes and sizes. body of the shrink head casing is-irst molded and then dipped intoa bath composed of silica sand, water, cement, and molasses in such manner as to apply the required alnount of such material to the' core, and then the vent holes may be formed by drilling, or in other suitable way.

The accompanying drawing shows a vertical section of the upper part of an ingot mold and a vertical section of a shrink head casing applied thereto constructed in accordance with my invention. A portion of the ingot is also illustrated.

The mold is indicated at M, the ingot at I, its cavity at C, and the shrink head casing is indicated at E. The core, or body of the Preferably the' shrink head casing. is indicated at m, and its covering at y. The core of the casing is composed of slowly combustible material such as charcoal, coal, or coke mixed with binding material Isuch as cement, preferably Portland cement, in the proportions by weight of 80% combustible material, and 20% binding material. The covering, y, is composed ofnon-combustible material, preferably silica sand, and molasses, in the proportions by weight of silica sand 7 5%, water 20%, and molasses 5%.

The feeder is provided with holes z which extend through the top of the covering y. These are vent holes for the purpose of allowing such gases as may be generated to pass out.

A shrink head casing thus constructed serves to conserve the heat of the upper por- 'tion of the ingot while being cast. The molten metal remains liquid to such an. eX- tent as to cause the pipe to be filled toa level above the bottom of the casing, and the casing as a whole is strong and of relatively low weight, and may be manufactured at relatively low cost.

In the manufacture of my shrink head casing the core w is first .molded in any usual way, and when cold is di pcd into a bath composed of silica sand silica iour), molasses and water, in thea proportions abbve specified. The bath has the consistency ofv thick molasses and it is heated to a temperature preferably of about 150 F. AThe core m when cold is dipped into Ethis bath and receives a coating y of approximately oneeighth of an inch thickness. After beingthus dipped and after having received said coating, the casing as a whole is baked at a temperature above the boiling point of water, preferably at a temperature of 250 F., until it is thoroughly dry and hard. The coating being siliceous resem-bles glass, and it is extremely hard and stron v It will be observed t at the combustible material does not come into direct contact with the molten metal of the ingot, and that no gas from the combustible material can pass through the coating to the ingot. My shrink head casing therefore has an advantage over some feeders or shrink head casings heretofore employed.

Inasmuch as the coating y is non-combustible and is of substantial thickness' and strength and inasmuch as its melting point is below that of liquid steel, the casing as a 5 usual way.

I claim as my invention:

1. A shrink head casingfor ingot molds comprising a self-supporting core consisting of sloivly combustible material and a nony 10 metallic self-supporting casing, which completely surrounds the core, composed of noncombustble material, but having vent holes at its upper end.

2. A shrink head easingfor ingot molds 15 comprising a self-supportingl core consisting of siliceous material which completely .sur-

rounds the core having only vent holes at its upperend.

3., A shrink head casing for ingot molds f comprising a self-supportiug` core composed of slowly combustible material and a binder and a covering therefor consisting of silica sand and a binder which completely surrounds the core, but having vent holes at the top for the escape of gases.

In testimony whereof, I have hereunto subscribed my name.

' EMIL GATHMANN. 

